The overall objective of this project is to determine the control mechanisms of protein and nucleic acid metabolism of ascites tumor cells with emphasis on the controlling role of nucleotides. One of the immediate goals is the elucidation of the mechanism for the activation of protein breakdown in ATP-rich cells and for the conservation of cellular proteins in living tumor cells with low energy supply. Controlled depletion of cellular ATP will be implemented by means of 2- deoxyglucose and other inhibitors of energy metabolism. The proteins of the mouse tumor cells will be labelled with radioactive arginine and other essential amino acids. The rate of release of labelled amino acids from the rapidly and slowly degrading proteins in the tumor cells maintained at different metabolic states in the presence of cycloheximide and other inhibitors of protein synthesis will be studied. The effects of incorporation of amino acid analogs on protein metabolism will be investigated.